Friction clutch



Aug. 19, 1941.

H. NUTT ETAL FRICTION CLUTCH Filedfsept. 15, 1959 Patented Aug. 19, 1941 FRICTION CLUTCH Harold Nuit and Leo` W.

signors to Borg-Warner Corporation, Chicago, Ill., acorporation of Illinois Application september 15, 1939, seri-a1 No. 295,004

i 18 Claims. (o1. 19a- 68) This invention relates to friction clutches and has as its primary object to provide a clutch of maximum compactness, particularly in an axial direction. To this end, the invention contemplates an arrangement wherein the pressure for engaging the clutch is supplied by `a remote pressure spring and is applied through a series of operating levers arranged for maximum compactness and simplicity.

More specifically, the invention aims to provide an improved construction and arrangement of such operating levers and means whereby said levers are fulcrumed with respect to the driving member of the clutch, `so as to take the reaction of the clutch engaging thrust. e e

Another object of the invention is to provide, in a clutch having thecharacteristics set forth above,` an improved drivingY connection between the driving member and the pressure plate, in the form of a series of elongated flexible driving links, each having one end attached tothe pressure plate and theV other'end attached to the fulcrum or reaction member. The inventionfurther contemplates, in `this respect, the provision of a reaction member in the form of an annulus which in addition to connecting one endof` each driving linkto the driving member, is adapted to form a series of fulcrums for the operating levers.

The invention further aims, in this respect, to provide a reaction member that is simple and inexpensive in construction, and provides a compact arrangement wherein the driving links are accommodated `by regions of the reaction member intervening between the lever fulcruming portions thereof, substantially the entire circumference of the reaction member being thus utilized i by the driving links and the levers. The regions of the reaction member which accommodate the driving links are straight and are normal to radii of the clutch axis, being preferably bisected by said radii so that the driving links may be disposed chordally with respect to the pressure plate, and may register with saidregions so as to be completely covered andprotected thereby and yet allow said regions to be comparatively narrow in width. In this respect, the invention aims to economize by utilizing a reaction member which is quite narrow in `radial cross-section. This is made possible, first, by the driving link arrangement alluded to above, and second, by the fact that the operating levers, instead of being release levers as in the conventional clutch, are of a type adapted to apply vpressure to the pressure plate, and therefore may be fulcrumed at Cook, Chicago, Ill., as-

their outer ends instead of in their intermediate-regions, with respect to the reaction member. Other and more particular objects, advantages and uses of our invention will become apparent from a reading of the following specification taken in connection with the appended drawing which forms a part thereof and wherein:

Fig. 1 is a rear elevation of a portion of a fric.. tion clutch embodying Vthe invention, parts thereof being broken away and shown in section to better illustrate the' construction.

Fig. 2` is an axial sectional view taken as indicated by the line 2-2 of Fig.`1;

Fig. 3 is a chordal sectional view thereof taken as indicated by the line 3-3 of Fig. 1; and

Fig. 4 is a detailed radial sectional view thereof taken as indicated by the line 4-4 of Fig. 1.

As an example of one form in which the invention may be embodied, we have shown in the drawing a friction clutch of the type suitable for embodiment in a motor vehicle, the engine flywheel of which, indicated at I0, comprises the driving member of the clutch. Between the friction face II of the flywheel I 0, and the friction face I2 of thepressure plate I3, a driven plate, indicated generally at Ill, is adapted to be engaged.

Pressure for moving the plate I3 into engagement with the driven plate I 4 is provided by a remote pressurespring and linkage of the type shown in the pending application, Serial No. 284,606, of Harold NuttQforgriction clutch. The transmitting linkage includesathrust collar I5,` surrounding the driven shaft I6 up'mwhichthe driven plate Id is mounted, erating levers I'I the intermediate regions of which are in thrust transmitting association with the pressure plate I3 through the medium of T-shaped thrust elements I8 eachincluding a head portion I9 engaged in a recess 20 formed in the lever I'I, and a leg portion 2l piloted in a hole 22 in the pressure' plate I3. The shoulder regions of the head I9, opposite the side which is engaged in the recess 20, engaged against the rear face of the pressure plate I3, provide thrust contact with the pressure plate. The piloting of the 1eg,2I in the hole 22 limits thepossible tilting of the thrust element so as to maintain the proper thrust connection. The head I9 is embraced between side flanges 23 of the lever I1 and thereby confined against lateral displacement with relation to the lever.

`The inner ends of the levers I'I are formed and a series of op?N` with arcuate lingers 55 adapted to receive thrust from the collar I5.

The outer end of each lever I1 is provided with a fulcrum finger 24, which is fulcrumed with respect to the flywheel I5, through the medium of a reaction member 25. The reaction member 25 is roughly Z-shaped in cross section, including an outer radial flange 2li, by means of which it is attached to the ilywheel, an inner radial flange 21, and an axial wall 28 joining the flanges Z5 and 21.

The axial wall 23 is provided with a series of fulcrum apertures 29 through each of which the fulcrum ringer 24 of a lever I1 is extended. The finger 24 is fulcrumed against the regionl 3l) of the wall 28 defining the rear extremity of the aperture 29. l v

The ulcrum ringer 24 is provided in its respective sides with notches 3| which receive the regions of the wall 28 defining the circumferential extremities oi the aperture 29 and which provide, in the fulcrum finger 24 of the lever, opposed shoulders 32 and 33 engaging the opposite sides of the Wall 28 so as to restrain the lever I1 against radial displacement either inwardly or outwardly. Axially forwardly of the region of the aperture 29 in which the linger 24 is received in the assembled position of the clutch, the aperture 29 is elongated circumferentially as at 34, suiiiciently to allow insertion and removal of the fulcrum finger 24.

The inner radial flange 21 of the reaction member partially overlies the pressure plate I3. It has two functions, one of which is to brace and strengthen the axial wall 23 so as to prevent any yielding thereof in a radial direction, and the other of which is to form a pocket for the accommodation of the flexible driving links which will now be described.

The flexible driving links 35 are in the form of flat strips, preferably of spring steel, each having one end attached to the rear face of the pressure plate I3 as by means of a rivet 36 and having its other end attached, as by means of a rivet 31, to a depressed region 38 of the ange 21, extending toward the pressure plate I3 to a position just short of the rear face thereof.

The driving link 35 lies substantially in the plane of the rear face of the pressure plate I3.

Secured beneath the head of the rivet 33 is a retainer cup 3S extending through an opening 45 in a depression 4I inthe reaction member 25, and having a ange 42 adapted to cooperate with the depression-4I so as to limit the possible sepa- ,ration-ofthe pressure plate and reaction member when detached from the ilywheel I3. The depression 4I is of suiiicient depth that at no time can the flange 42 projectbeyond the rear face of the ange 21 of the reaction member.

The invention achieves an improved compactness making the clutch particularly suitable in connection with automatic or semi-automatic transmissions which require that the space available for the engine clutch be reduced to a minimum, Along with such compactness, the invention combines a most desirable arrangement of the ilexible driving link. In addition, maximum economy of construction is obtained.

The flexible driving link, which has the basic advantage of providing a noiseless driving connection between the reaction member and the pressure plate which allows these two members to freely move axially with respect to each other while the driving connection is maintained, is arranged chordally with respect to the pressure plate, with the rivets 36 and 31 equi-distant from the axis of the clutch and equi-distant from the radius to which the driving link is normal. The reaction member is formed with alternating fulcrum portions 43 and driving link pockets 44, whereby the driving links may be equi-distantly spaced around the circumference of the clutch, and accommodated in those regions of the reaction member which intervene between the lever fulcruming regions. Thus the entire circumference of the reaction member is utilized, and the fulcrum levers and driving connections may lie roughly in the same plane, thereby contributing to the axial compactness of the clutch. The driving link pockets 44 are straight, and register with the links 35, being just enough wider than the links so as to completely cover and protect them. The outer edges of the links 35 are positioned closely adjacent the wall portions 28 of the pockets. Because the links 35 are arranged chordally, it is possible to form the reaction member in the shape of a symmetrical polygon and at the same time to achieve the snug arrangement vjust discussed. The chordal arrangement of the driving links is most desirable for the reason that it avoids the development of radial components in the forces transmitted through the links.

The clutch is assembled by inserting the operating levers I1 through the wider portions 34 oi' the apertures 29 until the notches 3l register with the wall 28, and the levers are then moved into the narrow regions of the apertures 29. The struts I8 are then interposed between the levers and the pressure plate I3, as the latter is moved into operative relation to the levers, and subsequently the links 35 are attached to the pressure plate by means of the rivets 36, the retainer cups 39 being attached at the same time. This serves to secure the pressure plate, reaction member, and operating levers in loose assembled relation in which they may be freely handled without being able to become dissociated from their proper operative positions relative to one another. To this end, the fulcrum regions 43 of the reaction member are 4provided with steps 45 and the latter are provided with projections 46 against which the fulcrum fingers 24 of the levers are adapted to engage to limit the extent to which the fingers 24 may move toward the enlarged regions-34, at positions out of registry with said enlarged regions 34, in any of the positions of separation of the pressure plate and reaction member permitted by the retainer cups 39. The only manner in which the levers can be detached from their ulcrums after the clutch has been assembled, is Vby removingthe rivets 36 and the retainer cups 39, then moving the pressure plate away from the reaction member so as to allow the levers I1 to be tilted to the left as viewed in Fig. 2, sufficiently to bring the ngers 24 into registry with the enlarged regions 34 of the apertures 29.

In the operation of the clutch, pressure is adapted to be applied to the inner ends of the operating levers I1 from the remote pressure springs hereinabove mentioned. Fulcruming against the fulcrum regions 43 of the reaction member, the levers I1 will swing to the left as viewed in Fig. 2, exerting thrust through the elements IS against the pressure plate I3 and thereby causing the clutch to become engaged. The clutch'is disengaged byremoving the load 'of the remote pressure springs from Vthe collar I5 in any suitable manner.

`2,253,344 The' fingers 24 uofntheoperating levers are formed in substantially the ,same` plane as the forwardA regions of the side flanges 23, and are connected to the intermediate, regions of maximum thickness, by the inclined portions 4l, which are adapted to clear the flange 2l of the reaction member sufficiently to allow the levers Il the necessary radius 'of operating movement.

We claim:

. 1. In a friction clutch, anr annular reaction member, generally polygonal and roughly Z- shaped in cross section, comprising an outer radial flange adapted to be attached to a driving member, an inner radial flange, and an axial wall joining said flanges and having spaced fulcrum apertures, a plurality of operating levers@ fulcrumed in said apertures, a pressure plate dis` posed between said reaction member and the driving member, and a plurality of flexible driv^ ing links disposed betweensaid inner flange and the pressure plate, .chordal to the pressure plate, registering with regions of said inner flange in terveningbetween,` said fulcrum apertures, and attached at their respective ends to the pressure i plate and said inner flange respectively.

2.`In `a friction clutch, an annular reaction member, generally in the form of a polygon, the

sides of which comprise alternately arranged lever fulcrum portions and driving element pockets, a pressure plate, an operating lever ful-V crumed in each of said. fulcrumportions, and a flexible driving link disposed in each of `said pockets, chordal tothe pressure plate, substantially parallel tothe plane of the'pressure plate, and attached at its respective ends tothe pressure plate and reaction member respectively.

3. In a friction clutch, a driving member, an annular reaction member secured thereto, a pressure plate disposed between the driving member and the reaction member, a driven plate disposed between the pressure plate and the driving member, a pluralitycf operating levers arranged radially with their outer `ends fulcrumed on the reaction memben; their intermediate regions in thrust transmitting association with said `pressure plate and their inner ends adapted to receive thrust for packing said, driven member between the pressure plate andthe driving member, and a plurality `of `flexible driving links disposed between the` reactien` member and the pressure plate in positions normal to radii of the clutch axis and registering with portions of the reaction member intervening between said operating levers, said driving links being attached at their respective ends to said portions and to the pressure plate respectively.

4. A friction clutch as vdefined in claimV 3,

wherein said driving links are substantially bisected longitudinally by the radii to which they are normal.

5. A friction clutch as defined in claim 3, wherein said reaction member is narrow and substantially Z-shaped in cross section, including an outer radial flange by which it is attached to the driving member, an inner radial flange overlying said flexible driving links, andthe peripheral region of the pressure plate, and an axial wall connecting said flanges and provided with apertures in which said levers are fulcrumed.

6. In a friction clutch, a driving member, a pressure plate, a driven plate, an annular reaction member, substantially Z-shaped in cross section, comprising an outer radial flange attached to the driving member, an inner radial flange overlyingthe pressure plate, and an axialr wall connecting said flanges and provided with circumferentially spaced fulcrum openings, a plurality of operating levers arranged radially with their outer ends fulcrumed in said openings, their -intermediate regions in thrust transmitting associa-tion with the pressure plate and their inner ends adapted to receive thrust for packing said driven plate between the pressure plate and the driving member, and a plurality of flexible driving links disposed between said inner flange and the pressure plate in positions chordal to the pressure plate and attached at their respective ends tothe pressure plate and said inner flange respectively.

'7. A friction clutch' as defined in claim 6, wherein said reaction member is in the form of a `polygon, alternate sides of which comprise the lever fulcrum regions and the intervening sides of which accommodate the flexible driving links.

` of flat strips parallel to the Vplane of the pressure lplate, and the reaction member includes radial by", radii of the clutch axis, and wherein said flexible driving links are disposed in alignment with said regions,between said regions and the pressure plate.

l0. An axially shallow' friction clutch comprising a driven plate, a pressure plate, an annular reaction member, axially shallow and roughly Z-shaped in cross-section, comprising an outer radial flange adapted to be attached to a driving member, an inner radial flange partially overlying the pressure plate, and an axial wall joining said flanges and providing a plurality of circumferentially spaced lever fulcrum portions, and radially disposed operating levers having their 1: outer ends fulcrumed on said fulcrum portions, their intermediate regions in clutch engaging thrust-transmitting association with said pressure plate, and their inner ends arranged to receive clutch engagingV thrust, said intermediate regions being substantially coextensive in an axial 12. A friction clutch as defined with a fulcrum aperture through which the corresponding lever is extended, and the said axial wall portion is formed, between the outer flange and the fulcrum aperture, with a radially outwardlyprojecting step against which the outer end of the lever is adapted to engage to limit the possible swinging movement of the lever when the reaction member is detached from the driving member.

13. In a friction clutch, a pressure plate, an

annular reaction member adapted to be attached to a driving member and having a radial flange region between which and the driving member the pressure plate is adapted to be positioned,

5 flange regions between which, andthe pressure plate, said strips are disposed.

which is received v wherein said fulcrum portions are each provided and a nexible driving link disposed between the plate, fulcrumed on said reaction member, said pressure plate-and said ll'ange region, a securing levers having intermediate regions that are subelernentr attaching-one end of said driving link stantially coextensive in axial dimension with tothe rear-face of the pressure plate, a flanged the space between the rear face of the pressure retainer-cup alsolsecured by said rivet, said flange 5l plate and the plane of the rear extremity of the region having a pair of spaced depressions exreaction member, and a pluralityof flexible drivtendi-ng toward the pressure plate, one of said ing links disposed between said inner flange and depressions being attached to the other end of the lthe pressure plate, chordal to the pressure plate, flexible driving element and the other depression registering with regions of said flange intervenreceiving said retainer cup and cooperating with 1() ing between said fulcrum apertures, and attached the flange portion thereof to limit the separation at theirrespective ends to the pressure plate and of the pressure plate and said reaction member. f said ange respectively.

14. In a friction clutch, a pressure plate, a 17.. An'axiallyshallow friction clutch compriscover having a centrally apertured depressed reling a driving member, an annular reaction mem- 'Qr secured thereto, a pressure plate disposed etween thedriving `member and the reaction member, a driven plate disposed .between the gion extending toward the pressureplate, and 1515"? a member for limiting the separation -of said cover and plate, comprising a sheet metal cup secured to the pressure plate, extendingA through *Y g pressure plate and the driving member, a pluthe aperture inl said depression, andlravi-irig` at -ality of radially arranged'levers for controlling its rim aflange extending radially outwardlyx of the movement of said pressure plate, fulcrurned for eng-agement withthe' wallofjsaid' depression ""f l'on said reaction member, said levershaving in rtermediate .regions that are'substantially coextensivefin. axial' 'dimension with the space be- VYtween the rear face of the pressure plate and vthe plane ofthe rear extremity of the reaction member, and a plurality of flexible driving links 15. aidally'shallowfrliction clutch comprising ai'driverrplate, a pressure plate, an annular reaction member ci-rcumscribing a space in which the pressure plate is-reeeived, said reaction member having a plurality of -fulcrum portions disdisposedjbetweeir the reaction memberv and the posed forwardly-of theplane of its rear extremity, pressure plate, extending generally in circumferand a plurality of operating levers having inter ential directions,l and disposed circumferentially mediate regions'substantially -coextensiveaxially 3b. intermediate said operating levers, said driving with the space betweenrthe rear surface -of the linlizsleing attached at their ends to said reaction pressure plate and said plane, said intermediate f v jmember-and pressure plate respectively. regions being in thrust transmitting association 1 18. An axially Ys"n`a'.llovv friction clutch comprisvvithv the pressure plate, said levers being-'tapered ing a` driven plate, a pressure plate, an annular forwardly from said intermediate regions to their as reaction member CrCuIlSCl'bng a Space in Which outer ends an'd having saidouter ends'fulcrumed the pressure plate is received, said reaction memagainst said fulcrum portions', the linner ends ber having a plurality of fulcrum portions disof said levers being adapted ,to receive clutch posed forwardlyrof the plane of its rear extremengaging thrust directed'tow'a'rd the pressure f ity, ,and a plurality of operating levers having plate. intermediate regions substantially coextensive 16. An axially shallow friction clutch comprisaxially with the space between the rear surface ing a driving member, an annular reaction memof the pressure plate and said plane, said inber secured thereto, said reaction member includ- Yterrnediatev reg-ions being in thrust transmitting lg an axial Wall hVng 2 flange @Xtendng inas'socation with the pressure plate, the outer ends wardly from the rear extremity thereof, a pres- 4;, of the levers being fulcrumed on said fulcrum sure plate disposed between the driving member portions, andthe inner ends-of the levers being and the reaction member, a driven plate disarranged to receive clutch engaging `thrust. posed between the pressure plate and the driving Y member, a plurality of radially arranged levers HAROLD NUTT.

for controlling the` movement of said pressure 50 Y LEO W. COOK. 

